1. Field of the Invention
The present invention generally relates to a powder of oxide which is a material for a dielectric ceramics comprising perovskite-type double oxide containing lead; and to a process for producing dielectric ceramics using the powder. The dielectric ceramics are used for making electrical parts; such as, capacitor, filter, and microwave generator or the like.
2. Description of the Relevant Art The dielectric ceramics which are produced by sintering synthesized powder of perovskite-type double oxide containing lead (e.g., lead zirconate titanate [Pb(Zr,Ti)O.sub.2 ]) has practical applications in various fields as a material for dielectrics. There are many processes for producing powder made of dielectric ceramic materials including synthesized powder of perovskite-type double oxide containing lead. A production process for such a powder by means of hydrothermal reaction is disclosed in, for example, Japanese Patent Laid-Open Publication No.85014/88, wherein a homogenous and fine powder is obtained.
Recently, a process for producing powder in perovskite-type double oxide containing lead by means of hydrothermal reaction has been developed for providing powder of homogeneous component and dielectric property. Since the raw powder, produced by means of the hydrothermal reaction, of dielectric ceramics not only has homogenous component, but also fine particles, it is better than a raw powder that is produced by means of solid reaction with respect to low sintering temperature.
However, when the powder synthesized by means of hydrothermal reaction is mixed with a binder, compressed and molded, the density of the compacted powder before sintering is low. Therefore, shrinkage ratio during the sintering operation becomes high, and deformation and cracks tend to occur.